Head-mounted display (HMD) devices are widely used in virtual and augmented reality applications. For example, virtual reality headsets have been used as wearable aids to assist those living with low vision or other vision impairments and disabilities. As HMD's may sometimes be used for long stretches of time, it would be useful to provide accessories or auxiliary devices that facilitate comfortable and effective use of HMD's.
Like reference numerals are used in the drawings to denote like elements and features.